A simple turbidimetric flow injection system for saccharin determination in sweetener products

A new method for saccharin determination in liquid sweetener products was developed. The method is based on the precipitation reaction of Ag(I) ions with saccharin in aqueous medium (pH 3.0), using a flow injection analysis system with merging zones, the suspension was stabilized with 5 g L⁻¹ Triton X-100. All experimental parameters influencing the flow injection system were optimized by means of chemometric approaches. The linear analytical curve was built from 2.4 g L⁻¹ up to 9.64 g L⁻¹ (r = 0.9968) with a quantification limit of 2.40 g L⁻¹. The precision assessed as relative standard deviation (n = 10) was found to be 1.75 % for the saccharin concentration of 7.20 g L⁻¹. Based on interference studies performed with the substances commonly found in liquid sweeteners, such as sodium cyclamate, methylparaben, sodium aspartame, and benzoic and citric acids, at the analyte to interferent mole ratio of up to 1: 10, no interference with the saccharin determination was observed. The presence of chloride ions interferes with the method, but a preceding liquid-liquid saccharin extraction with ethyl acetate was successfully employed to overcome this drawback. Accuracy of the method in sweetener products was evaluated by a comparison with the HPLC method.